The Seine River: France's Iconic Waterway Through Paris and History

The Seine (776 km / 482 mi) is France's second-longest river (after the Loire) and the longest entirely within French territory. It rises at Source-Seine in Côte-d'Or, flows northwest through Troyes, Fontainebleau, Paris, Mantes-la-Jolie, and Rouen, before entering the English Channel between Le Havre and Honfleur.

Key Features

• Navigable: Ocean-going vessels reach Rouen (120 km inland); connected to major canals (Marne, Oise, Yonne).
• Basin: Drains 78,650 km² (30,370 sq mi), covering most of the Paris Basin.
• Tributaries: Yonne (south), Marne and Oise (east) converge near Paris.

Paris and the Seine

The river bisects Paris into Rive Droite (Right Bank) and Rive Gauche (Left Bank), lined with UNESCO World Heritage quays. It enabled Paris's medieval growth as a trade hub, inspired Impressionists (Monet, Renoir), and remains central to civic life—bateaux-mouches, riverside cafés, and the 2024 Olympic opening ceremony.

Environmental Challenges

• Pollution: Industrial, agricultural, and combined sewer overflows (CSOs) degrade water quality; swimming banned since 1923 (aiming for 2025 return).
• Flooding: 1910 flood (8.6 m) set benchmark; climate change increases extreme rainfall risk.
• Restoration: €1.4B cleanup plan targets CSO capture, wetland restoration, and biodiversity recovery.

The Seine is more than a river—it's the liquid spine of French history, culture, and identity.